This invention relates to a class of metal complexes, the ligands used to prepare these metal complexes, polymerization catalysts derived therefrom, and the resulting polymerization processes using the same. More particularly, such metal complexes are characterized by a nitrogen containing aliphatic or cycloaliphatic moiety that is substituted with one or more aryl groups, an aryl-substituted silane bridging group, or one or more Group 14 organometalloid substituents on the metal.
EP-A-923,589, which is equivalent to WO98/06727, published Feb. 19, 1998, disclosed Group 4 metal complexes containing a heteroatom substituent at the 3-position of the cyclopentadienyl, especially indenyl, ligand groups. Particular heteroatom containing substituents included dihydrocarbylamino substituents including dimethylamino, diethylamino, methylethylamino, methylphenylamino, dipropylamino, dibutylamino, piperidinyl, morpholinyl, pyrrolidinyl, hexahydro-1H-azepin-1-yl, hexahydro-1(2H)-azocinyl, octahydro-1H-azonin-1-yl, and octahydro-1(2H)-azecinyl.
EP-A-577,581 discloses unsymmetrical bis-Cp metallocenes containing a fluorenyl ligand with heteroatom substituents. E. Barsties; S. Schaible; M.-H. Prosenc; U. Rief; W. Roll; O. Weyland; B. Dorerer; H.-H. Brintzinger J. Organometallic Chem. 1996, 520, 63-68, and H. Plenio; D. Birth J. Organometallic Chem. 1996, 519, 269-272 disclose systems in which the cyclopentadienyl ring of the indenyl is substituted with a dimethylamino group in non-bridged and Si-bridged bis-indenyl complexes useful for the formation of isotactic polypropylene and polyethylene.
Disclosure of random heteroatom substitution in mono-Cp metallocenes is found in EP-A-416,815, WO 95/07942, WO 96/13529, and U.S. Pat. Nos. 5,096,867 and 5,621,126. Specific heteroatom substitution of the 3- and 2-position of indenyl complexes of group 4 metals was disclosed in WO98/06727 and WO/98/06728 respectively.
Despite the advance in the art, particular higher use temperature, obtained by such prior art metal complexes as were disclosed in the foregoing reference, there remains a desire for improved metal complexes capable of even further increase in use temperature that are still capable of forming catalyst compositions useful in producing polymers having high molecular weights and, for ethylene/higher xcex1-olefin copolymers, high incorporation of comonomer. The subject compositions of this invention show unexpected improvement in these desirable features.
According to the present invention there are provided metal complexes corresponding to the formula: 
where M is a Group 4 metal that is in the +2, +3 or +4 formal oxidation state;
RA independently each occurrence is hydrogen, or a hydrocarbyl, halohydrocarbyl, hydrocarbyloxyhydrocarbyl, dihydrocarbylaminohydrocarbyl, dihydrocarbylamino, hydrocarbyloxy, hydrocarbylsilyl, or trihydrocarbylsilylhydrocarbyl group of from 1 to 80 atoms, not counting hydrogen, or further optionally, two or more RA groups may be covalently linked together;
Z is (RD)2Sixe2x95x90, wherein RD independently each occurrence is C7-20 alkaryl or two RD groups together are alkyl- or polyalkyl-substituted arylene of up to 40 carbons; and
Y is bonded to M and Z and is selected from the group consisting of xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94NRExe2x80x94, and xe2x80x94PRExe2x80x94; wherein, RE independently each occurrence is hydrogen, or a member selected from hydrocarbyl, hydrocarbyloxy, silyl, halogenated alkyl, halogenated aryl, and combinations thereof, said RE having up to 20 nonhydrogen atoms
X is an anionic or dianionic ligand group having up to 60 atoms exclusive of the class of ligands that are cyclic, delocalized, xcfx80-bound ligand groups;
Xxe2x80x2 independently each occurrence is a neutral ligand having up to 40 atoms;
p is zero, 1 or 2, and is two less than the formal oxidation state of M when X is an anionic ligand, and when X is a dianionic ligand group, p is 1; and
q is zero, 1 or 2.
The above complexes may exist as isolated crystals optionally in pure form or as a mixture with other complexes, in the form of a solvated adduct, optionally in a solvent, especially an organic liquid, in the form of a dimer or chelated derivative thereof, wherein the chelating agent is an organic material, preferably a Lewis base, especially a dihydrocarbylether, cyclic aliphatic ether, trihydrocarbylamine, trihydrocarbylphosphine, or halogenated derivative thereof, or as a polymeric or crosslinked polymeric product, wherein one or more RA groups are polymerized with one another or copolymerized with an ethylenically unsaturated comomomer.
Also, according to the present invention, there is provided a catalyst composition, useful, inter alia, for the polymerization of addition polymerizable monomers, comprising the following components or the reaction product thereof:
(A) one or more metal complexes of formula (I) or (II); and
(B) an activating cocatalyst, wherein the molar ratio of (A) to (B) is from 1:10,000 to 100:1.
Another embodiment of this invention is the foregoing catalyst composition wherein the metal complex is in the form of a radical cation.
Further according to the present invention there is provided a polymerization process comprising contacting one or more addition polymerizable monomers under polymerization conditions with one of the aforementioned catalyst compositions.
A preferred process of this invention is a high temperature solution polymerization process comprising contacting one or more addition polymerizable monomers under polymerization conditions with one of the aforementioned catalyst systems at a temperature from 50xc2x0 C. to 250xc2x0 C., preferably from 150xc2x0 C. to 250xc2x0 C., most preferably from 175xc2x0 C. to 220xc2x0 C. Within the scope of this invention are the polymeric products produced by the aforementioned processes.
This invention also includes the precursor of the delocalized electron containing, cyclic moiety of the metal complex of formula (I), said precursor corresponding to the formula: 
wherein, Yxe2x80x2 is xe2x80x94ORC, xe2x80x94SRC, xe2x80x94NRCRE, xe2x80x94PRCRE;
RC independently each occurrence is hydrogen, an alkali metal cation, or a magnesium halide cation, or both RC groups together are an alkaline earth metal dication;
Z* is (RD)2Sixe2x95x90, wherein RD independently each occurrence is C7-20 alkaryl or two RD groups together are alkyl- or polyalkyl-substituted arylene of up to 40 carbons; and
RA and RE are as previously defined.
It is to be understood that the foregoing formulas (IA) and (IIA) depict one of several equivalent interannular, double bond isomers, and that all such isomeric structures are intended to be included by the formulas.
The final embodiment of the invention is the use of one of the foregoing compounds of formula (IA) or (IIA) in a synthesis to produce a Group 4 metal complex of formula (I) or (II).
The present catalysts and processes are especially suited for use in the production of high molecular weight polymers of olefin monomers, over a wide range of polymerization conditions, and especially at elevated temperatures, with exceptionally high catalyst efficiencies. They are especially useful for the solution polymerization of ethylene homopolymers, copolymers of ethylene with an xcex1-olefin other than ethylene (ethylene/xcex1-olefin copolymers), and ethylene/propylene/diene interpolymers (EPDM polymers) wherein the diene is ethylidenenorbornene, 1,4-hexadiene or similar nonconjugated diene. The use of elevated temperatures dramatically increases the productivity of such processes due to the fact that increased polymer solubility at elevated temperatures allows the use of increased conversions (higher concentration of polymer product) without exceeding solution viscosity limitations of the polymerization equipment as well as reduced energy costs needed to devolatilize the reaction product. In the preparation particularly of copolymers of ethylene and at least one xcex1-olefin comonomer, the present catalyst compositions incorporate relatively large quantities of non-ethylene comomomer compared to catalysts comprising a conventional metal. In particular, ethylene/1-octene copolymers having reduced density due to increased incorporation of 1-octene therein, may be made using the present catalyst compositions.
The metal complexes of this invention may also be supported on a support material and used in olefin polymerization processes in a slurry or in the gas phase. Additionally, those complexes wherein RA is ethylenically unsaturated may be used to form polymeric reaction products via polymerization of copolymerization of such ethylenic unsaturation in the RA moiety. Such products may be employed in a slurry or gas phase polymerization without need for an additional support material. Such a polymeric catalyst may be formed by prepolymerization of the functionalized metal complex, optionally with one or more ethylenically unsaturated monomers, in situ in a polymerization reactor or in a separate reactor with recovery of the prepolymerized catalyst prior to the primary polymerization process.